Hybrid powertrain in mixed design

Abstract

Hybrid transmission (18) for a motor vehicle drive train (12) of a motor vehicle (10), comprising: a first transmission input shaft (24) for operatively connecting the hybrid transmission (18) to an internal combustion engine (16) of the motor vehicle; a second transmission input shaft (26) for operatively connecting the hybrid transmission (18) to a first electric drive motor (14) of the motor vehicle (10); an intermediate shaft (30) which is drivingly connected to the first transmission input shaft (24); an output shaft (28); a first planetary gear set (RS1) for operatively connecting the hybrid transmission (18) with an output (36) which is connected to the intermediate shaft (30) and the output shaft (28); a countershaft (32); spur gear pairs (ST1, ST2, ST3, ST4, ST5) arranged in several gear set levels; and several gearshift devices with shift elements (A, B, C, D, E) for engaging gear steps, wherein a gear of a first spur gear pair (ST1) and a gear of a second spur gear pair (ST2) are drivingly connected to one another; the intermediate shaft (30) is drivingly connected to a sun gear or a ring gear of the first planetary gear set (RS1); a differential of the output (36) comprises a differential shaft which is designed as a solid shaft and is surrounded at least in sections by the intermediate shaft (30), the second transmission input shaft (26) and the output shaft (28); and an axial length of the differential shaft is greater than an axial length of the output shaft (28) and the differential shaft completely penetrates the output shaft (28).

Description

[0001] The present invention relates to a hybrid transmission, a motor vehicle drive train with such a hybrid transmission, a motor vehicle with such a motor vehicle drive train and a method for operating such a motor vehicle drive train.

[0002] Vehicles are increasingly being equipped with hybrid drives, i.e. with at least two different drive sources. Hybrid drives can help reduce fuel consumption and pollutant emissions. Drivetrains with an internal combustion engine and one or more electric motors as parallel hybrids or mixed hybrids have largely become established. Such hybrid drives feature an essentially parallel arrangement of the internal combustion engine and the electric drive in the power flow. This allows both a superposition of the drive torques and control with purely internal combustion engine drive or purely electric motor drive. Since the drive torques of the electric drive and the internal combustion engine can be added together depending on the control, a comparatively smaller design of the internal combustion engine and / or its temporary shutdown is possible.This allows for a significant reduction in CO2 emissions without any significant loss of performance or comfort. The possibilities and advantages of an electric drive can thus be combined with the range, performance, and cost advantages of internal combustion engines.

[0003] A disadvantage of the aforementioned hybrid drives is their generally more complex design, as both drive sources typically transmit power to a single drive shaft via a single transmission. This makes such transmissions complex and costly to produce. Reducing the complexity of a hybrid transmission's design usually results in a loss of variability.

[0004] This disadvantage can be at least partially overcome by dedicated hybrid transmissions (DHTs), in which an electric motor is integrated into the transmission to provide the full range of functions. For example, the mechanical transmission part of the transmission can be simplified, for example by eliminating the reverse gear and using at least one electric motor instead.

[0005] Dedicated hybrid transmissions can be derived from familiar transmission concepts, such as dual-clutch transmissions, torque converter planetary transmissions, continuously variable transmissions (CVTs), or automated manual transmissions. The electric motor is preferably integrated into the transmission.

[0006] From the published patent application DE 10 2013 215 114 A1, a hybrid drive of a motor vehicle is known, which has an internal combustion engine with a drive shaft, an electric machine operable as a motor and as a generator with a rotor, an automated manual transmission designed in countershaft design with an input shaft and at least one output shaft, and a superposition transmission designed in planetary design with two input elements and one output element.In this hybrid drive, the superposition gear is arranged coaxially above a free end of the output shaft, and the first input element of the superposition gear is connected in a rotationally fixed manner to a hollow shaft arranged coaxially above the output shaft. The hollow shaft is connected in a rotationally fixed manner to an idler gear of the immediately axially adjacent spur gear stage of the manual transmission via a coupling switching element for coupling the combustion engine, and in a rotationally fixed manner to the second input element or the output element of the superposition gear via a bridging switching element for bridging the superposition gear. Furthermore, the second input element of the superposition gear is permanently drive-connected to the rotor of the electric motor, and the output element of the superposition gear is connected in a rotationally fixed manner to the output shaft.

[0007] From published patent application DE 10 2020 104 791 A1, a transmission assembly is known that comprises a first transmission input shaft and a second transmission input shaft. The first transmission input shaft and the second transmission input shaft are coupled to a first planetary gear in a torque-conducting manner. Furthermore, a transmission output shaft of the transmission assembly is coupled to a second planetary gear in a torque-conducting manner. A first spur gear is arranged between the first planetary gear and the second planetary gear in the power flow. Furthermore, a drive unit for driving a first vehicle axle is presented, which drive unit comprises such a transmission assembly.

[0008] From the published patent application DE 10 2012 218 367 A1, a group transmission device with an electric machine, with a main transmission designed as a countershaft transmission, a front-mounted group connected upstream of the main transmission, and a rear-mounted group connected downstream of the main transmission is known. In the area of ​​the main transmission, the front-mounted group, and the rear-mounted group, a gear ratio can be changed via positive shifting elements that can be engaged and disengaged from the power flow. A torque of the electric machine can be introduced into the power flow in the area of ​​the front-mounted group, at least during a gear ratio change. According to the invention, the front-mounted group comprises at least three gear ratios that can be engaged and disengaged, the main transmission at least two gear ratios that can be engaged and disengaged, and the rear-mounted group at least two gear ratios that can be engaged and disengaged.

[0009] From the published patent application WO 2021 / 093 930 A1, a transmission arrangement for a hybrid drive is known, comprising: a multi-step transmission that can be connected to an internal combustion engine and has a clutch for transmitting an introduced rotary motion selectively via a first or a second shift stage; a reduction transmission that can be connected to the electric machine and that slows down an introduced rotary motion to a transmission transmission output part; a superposition transmission with a first input part that is drivingly connected to the multi-step transmission output part, a second input part that is drivingly connected to the superposition transmission output part, and with an output part; a differential transmission that is drivingly connected to the output part of the superposition transmission and that has two differential output parts for driving two side shafts;a controllable first clutch capable of locking two parts of the superposition gear; and a controllable second clutch for disengaging the differential gear.

[0010] Against this background, a person skilled in the art is faced with the task of creating a compact hybrid transmission with a simple mechanical design. Furthermore, a drivetrain configuration should preferably be implemented in which the hybrid transmission is positioned coaxially to the output shafts and the internal combustion engine and / or the electric drive motor can be arranged axially parallel to them.

[0011] This task is solved by a hybrid transmission for a motor vehicle drive train of a motor vehicle, with: a first transmission input shaft for operatively connecting the hybrid transmission to an internal combustion engine of the motor vehicle; a second transmission input shaft for operatively connecting the hybrid transmission to a first electric drive motor of the motor vehicle; an intermediate shaft which is drivingly connected to the first transmission input shaft; an output shaft; a first planetary gear set for operatively connecting the hybrid transmission to an output connected to the intermediate shaft and the output shaft; a countershaft; spur gear pairs arranged in several gear set levels; and several gearshift devices with switching elements for engaging gear steps, whereby a gear of a first spur gear pair and a gear of a second spur gear pair are drivingly connected to each other; and the intermediate shaft is drive-connected to a sun gear or a ring gear of the first planetary gear set.

[0012] The above object is further achieved by a motor vehicle drive train for a motor vehicle, comprising: a hybrid transmission as previously defined; an internal combustion engine that can be connected to the first transmission input shaft, and a first electric drive motor which is drivingly connected to the second transmission input shaft; wherein a differential of the output comprises a differential shaft which is designed as a solid shaft and is at least partially surrounded by the intermediate shaft, the second transmission input shaft and the output shaft; and an axial length of the differential shaft is greater than an axial length of the output shaft and the differential shaft completely penetrates the output shaft.

[0013] The above object is also achieved by a method for operating a motor vehicle drive train as previously defined.

[0014] The above task is finally solved by a motor vehicle with: a motor vehicle powertrain as previously defined; and an energy storage device for storing energy to supply the first electric drive machine and / or a second electric drive machine.

[0015] Preferred embodiments of the invention are described in the dependent claims. It is understood that the features mentioned above and those to be explained below can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the present invention. In particular, the motor vehicle drive train, the motor vehicle, and the method can be designed according to the embodiments described for the hybrid transmission in the dependent claims.

[0016] By providing a first transmission input shaft for operatively connecting the hybrid transmission to an internal combustion engine and a second transmission input shaft for operatively connecting the hybrid transmission to a first electric drive motor, a compact hybrid transmission can be created in a technically simple manner. An operative connection can be designed to be either switchable or non-switchable. In particular, a hybrid transmission can be created that is arranged around one of the vehicle shafts on the front axle, with the internal combustion engine and the first electric drive motor arranged axially parallel thereto. By providing a first planetary gear set connected to the first transmission input shaft, the intermediate shaft, and the output shaft, two electrodynamic superposition states can be created in a technically simple manner, enabling electrodynamic starting and electrodynamic gear shifting.Furthermore, a total of six purely electric gear ratios, three hybrid gear ratios, two purely combustion gear ratios, and a charge-to-neutral state can be configured. This allows for the creation of a hybrid transmission with a simple design, a compact construction, and low component stress. The hybrid transmission exhibits low transmission losses, good gearing efficiency, both in terms of the combustion engine and the electric drive, and is capable of powershifting and enables electrodynamic starting. Furthermore, the shifting elements are technically easy to access using actuators.

[0017] An output differential comprises a differential shaft, which is designed as a solid shaft and is at least partially surrounded by the intermediate shaft, the second transmission input shaft, and the output shaft. The axial length of the differential shaft is greater than the axial length of the output shaft. The differential shaft completely penetrates the output shaft. This allows the hybrid transmission to be advantageously arranged around the differential shaft, creating a compact drivetrain.

[0018] In a further advantageous embodiment, the hybrid transmission comprises a second planetary gear set, which is drive-connected to the first planetary gear set and a differential of the output. Preferably, a ring gear is fixed in the second planetary gear set, a planet gear carrier is drive-connected to the differential of the output, and a sun gear is drive-connected to a planet gear carrier of the first planetary gear set. A second planetary gear set makes it technically simple to achieve an output ratio of the power transmitted from the hybrid transmission to the differential shaft. In particular, an output ratio in the form of a second planetary gear set enables an advantageous, compact arrangement of the gear set to form the output ratio around the differential shaft. The functional scope of the hybrid transmission can be increased without significantly increasing the installation space required for the hybrid transmission.

[0019] In a further advantageous embodiment, a hollow output shaft is arranged on the countershaft. A planetary gear carrier of the first planetary gear set is drivingly connected to the hollow output shaft by means of a fourth spur gear pair. In addition, a differential of the output is drivingly connected to the hollow output shaft by means of a fifth spur gear pair. This allows an output ratio to be set up in a technically simple manner using the fourth spur gear pair and the fifth spur gear pair. Furthermore, an efficient bearing of the hollow output shaft on the countershaft can be achieved. A second planetary gear set for connecting an output can be omitted. The hybrid transmission can be designed to be compact in the axial direction.

[0020] In a further advantageous embodiment, the first spur gear pair and the second spur gear pair are connected to each other by a hollow shaft and arranged on the countershaft. This allows for improved support of the spur gears of the first spur gear pair and the second spur gear pair, which are arranged on the countershaft, because the hollow shaft provides a wider support.

[0021] In a further advantageous embodiment, a planetary gear carrier of the first planetary gear set is drive-connected to the output, wherein the sun gear of the first planetary gear set is drive-connected to the intermediate shaft, and the ring gear of the first planetary gear set is drive-connected to the output shaft. Alternatively, the ring gear of the first planetary gear set is drive-connected to the intermediate shaft, and the sun gear of the first planetary gear set is drive-connected to the output shaft. By connecting the sun gear to the intermediate shaft and the ring gear to the output shaft, the first electric drive motor can be operated at a low compensating speed during electrodynamic starting or electrodynamic shifting.By connecting the ring gear to the intermediate shaft and the sun gear to the output shaft, preferably only a small support torque is required from the first electric drive unit during electrodynamic starting and electrodynamic shifting. Furthermore, the first electric drive unit can operate in generator mode for longer during electrodynamic starting, since generator operation can be maintained for longer with increasing travel speed.

[0022] In a further advantageous embodiment, the second transmission input shaft, the intermediate shaft, and the output shaft are arranged coaxially with one another. In addition, the first transmission input shaft, the second transmission input shaft, the intermediate shaft, and the output shaft are designed as hollow shafts. Furthermore, the second transmission input shaft and the intermediate shaft surround the output shaft at least in sections. By designing the aforementioned shafts as hollow shafts and the coaxial arrangement, the compactness of the hybrid transmission can be further improved. In particular, the advantageous coaxial arrangement and the design of the shafts as hollow shafts enable the hybrid transmission to be arranged around the differential shaft, wherein the hybrid transmission and the differential shaft are arranged coaxially with one another.

[0023] In a further advantageous embodiment, the first transmission input shaft comprises an internal combustion engine clutch for releasably and driveably connecting the first transmission input shaft to the internal combustion engine. It is understood that the internal combustion engine clutch can be designed as a dog-type shift element or a friction shift element. An internal combustion engine clutch can decouple the internal combustion engine from the hybrid transmission, thus enabling a highly efficient, purely electric driving mode using the hybrid transmission. A friction clutch also enables a so-called momentum start of the internal combustion engine and can serve as a starting element for the internal combustion engine. An internal combustion engine clutch can increase the variability and efficiency of the hybrid transmission. Furthermore, an internal combustion engine clutch can be used in the hybrid transmission for functional safety reasons.

[0024] In a further advantageous embodiment, a first shifting element is designed to drive-effectively connect the intermediate shaft to the output shaft by means of the second spur gear pair and the first spur gear pair. A second shifting element is designed to block the first planetary gear set. A third shifting element is designed to drive-effectively connect the second transmission input shaft to the intermediate shaft. A fourth shifting element is designed to drive-effectively connect the first electric drive motor to the output shaft by means of the third spur gear pair and the first spur gear pair. Additionally or alternatively, a fifth shifting element is designed to drive-effectively connect the first electric drive motor to the output shaft by means of the second spur gear pair and the first spur gear pair.This advantageous arrangement of the shift elements allows the hybrid transmission to provide three hybrid gear ratios, some with multiple variants, six purely electric gear ratios, some with multiple variants, two electrodynamic overlay states, and at least one charge-to-neutral mode. A variable and compact hybrid transmission can be created that enables electrodynamic starting and electrodynamic shifting.

[0025] In a further advantageous embodiment, the shifting elements are designed as positive-locking shifting elements. Additionally or alternatively, at least two of the shifting elements, preferably four shifting elements, are designed as double-locking shifting elements and can be actuated by a double-acting actuator. Positive-locking shifting elements enable a highly efficient and cost-effective hybrid transmission. The technical design and operation of the hybrid transmission can be further simplified by a double-locking element. In particular, a double-locking element can be switched using a single actuator.

[0026] In a further advantageous embodiment, the motor vehicle drive train preferably comprises a further electric machine which is drivingly connected to the first transmission input shaft. The first electric drive machine and / or preferably the further electric machine can be controlled as a starter generator for starting the internal combustion engine. Additionally or alternatively, the first electric drive machine and / or preferably the further electric machine can be controlled as a charging generator for charging an energy storage device. The further electric machine is preferably designed as a high-voltage starter generator. This makes it possible to create an efficient motor vehicle drive train. In particular, fuel consumption can be reduced. It is understood that an additional starter for the internal combustion engine can be dispensed with since the first electric drive machine can tow the internal combustion engine.

[0027] In a further advantageous embodiment, an output of the hybrid transmission can be drive-connected to a first motor vehicle axle, wherein a second motor vehicle axle comprises an electric axle with a second electric drive motor. This makes it technically simple to create a hybrid drive train with all-wheel drive. Furthermore, the motor vehicle drive train can easily enable shifting without interruption in tractive force, since the electric axle can maintain tractive force during shifts in the hybrid transmission. Furthermore, a fail-safe drive train for a motor vehicle can be created, since a so-called serial driving mode can be set up in the event of a depleted energy storage device for the second electric drive motor.In the serial driving mode, the electric drive motor is preferably operated as a generator by the internal combustion engine, and the energy thus generated is made available to the second electric drive motor. Preferably, the first electric drive motor and / or the additional electric machine can be controlled as a generator to supply the second electric drive motor in order to establish a serial driving mode. This makes it possible to create a highly variable motor vehicle drive train in which driving and, in particular, starting can be carried out electrically, even when the energy storage device is empty.

[0028] Locking an element of a planetary gear set is understood in particular as blocking the element's rotation about its axis of rotation. Preferably, the element is connected in a rotationally fixed manner to a static component such as a frame and / or a transmission housing by means of a switching element. It is also conceivable to brake the element to a standstill.

[0029] Interlocking a planetary gear set involves connecting two gears and / or the planetary gear carrier and a gear of the planetary gear set in a drive-effective manner, so that they rotate together at the same speed around the same point, preferably the center of the planetary gear set. When interlocking two gears and / or a planetary gear carrier and a gear of the planetary gear set, the planetary gear set preferably acts like a shaft; in particular, no gear ratio is transmitted within the planetary gear set.

[0030] In this context, "drive-effectively connected" refers in particular to a non-switchable connection between two components intended for the permanent transmission of a rotational speed, torque, and / or drive power. The connection can be made either directly or via a fixed transmission ratio. The connection can be made, for example, via a fixed shaft, a gearing, in particular a spur gearing, and / or a belt drive, in particular a traction drive.

[0031] In this context, "drive-connectable," "can be connected to a drive," or "is designed for a drive-connected connection" refers, in particular, to a switchable connection between two components, which, in a closed state, is intended for the temporary transmission of a rotational speed, a torque, and / or a drive power. In an open state, the switchable connection preferably temporarily transmits essentially no rotational speed, no torque, and / or no drive power.

[0032] Stand-by charging or charging-in-neutral means, in particular, operating the electric drive motor as a generator, preferably when stationary with the combustion engine running, in order to fill an energy storage unit and / or to supply on-board electronics.

[0033] In this context, an actuator is, in particular, a component that converts an electrical signal into a mechanical movement. Actuators used with dual switching elements preferably perform movements in two opposite directions, switching one switching element of the dual switching element in the first direction and switching the other switching element in the second direction.

[0034] A gear change, particularly a serial shift, occurs in particular by disengaging a shifting element and / or a clutch and simultaneously engaging the shifting element and / or the clutch for the next higher or lower gear. The second shifting element and / or the second clutch thus gradually takes over the torque from the first shifting element and / or the first clutch until, at the end of the gear change, the entire torque is taken over by the second shifting element and / or the second clutch. With prior synchronization, a gear change can occur more quickly; positive-locking shifting elements can preferably be used.

[0035] An internal combustion engine can be any machine that can generate a rotary motion by burning a fuel such as gasoline, diesel, kerosene, ethanol, liquefied petroleum gas, LPG, etc. An internal combustion engine can be, for example, a gasoline engine, a diesel engine, a rotary engine, or a two-stroke engine.

[0036] In serial driving or crawling, an electric drive motor of a motor vehicle is powered by a combustion engine of the motor vehicle. The energy thus generated is then made available to another electric drive motor of the motor vehicle to provide drive power.

[0037] An electric vehicle axle, or simply an electric axle, is preferably a non-main drive axle of a motor vehicle, in which drive power can be transferred to the wheels of the motor vehicle by means of an electric drive motor. It is understood that the electric drive motor can also be connected via a transmission. Traction can be fully or partially maintained by means of an electric axle when a gear change occurs in the transmission for a main drive axle. Furthermore, all-wheel drive functionality can be implemented at least partially by means of an electric axle.

[0038] An electrodynamic starting element (EDA) ensures that the speed of the combustion engine and the electric drive motor is superimposed via one or more planetary gear sets, enabling a motor vehicle to start from a standstill with the combustion engine running, preferably without a friction clutch. The electric drive motor supports a torque. Preferably, the combustion engine can no longer be separated from the transmission by a starting clutch or the like. By using an EDA, the starter, generator, and starting clutch or hydrodynamic converter can be eliminated. In particular, an EDA is so compact that all components fit into the standard clutch housing without extending the transmission.The electrodynamic starting element can, for example, be firmly connected to an internal combustion engine, and in particular to a flywheel of an internal combustion engine, via a softly tuned torsional damper. This allows the electric drive motor and the internal combustion engine to be operated either simultaneously or alternatively. When the vehicle stops, the electric drive motor and the internal combustion engine can be switched off. Due to the good controllability of the electric drive motor, a very high starting quality is achieved, which can be equivalent to that of a drive with a torque converter clutch.

[0039] In an electrodynamic shift (EDS), as with EDA starting, the speed of the combustion engine and the electric drive motor is superimposed via one or more planetary gear sets. At the start of the shift, the torques of the electric drive motor and the combustion engine are adjusted so that the shift element to be disengaged is load-free. After this shift element is opened, the speed is adjusted while maintaining the tractive force, so that the shift element to be engaged becomes synchronous. After the shift element is closed, the load is distributed between the combustion engine and the electric drive motor as desired, depending on the hybrid operating strategy.The electrodynamic shifting system has the advantage that the shift element of the target gear to be engaged is synchronized through the interaction of the electric drive motor and the combustion engine, with the electric drive motor preferably being precisely controllable. A further advantage of the EDL shifting system is that high tractive effort can be achieved, since the torques of the combustion engine and the electric motor are combined in the hybrid transmission.

[0040] The invention is described and explained in more detail below using selected embodiments in conjunction with the accompanying drawings. They show: Fig. 1 a schematic plan view of a motor vehicle with a motor vehicle drive train according to the invention, Fig. 2 a schematic representation of the hybrid transmission according to the invention; Fig. 3a to 3c schematically show the switching states of the hybrid transmission according to the Fig. 2; Fig. 4 shows a further variant of a hybrid transmission according to the invention; and Fig. 5 a further variant of a hybrid transmission according to the invention.

[0041] In Fig. 1 schematically shows a motor vehicle 10 with a motor vehicle drive train 12. The motor vehicle drive train 12 has a first electric drive motor 14 and an internal combustion engine 16, which are connected to a front axle of the motor vehicle 10 by means of a hybrid transmission 18. In the example shown, the motor vehicle drive train 12 further comprises an optional electric axle with a second electric drive motor 20, which is connected to a rear axle of the motor vehicle 10. It is understood that a reverse connection can also be made, so that the hybrid transmission 18 is connected to the rear axle of the motor vehicle 10 and the front axle of the motor vehicle 10 comprises the electric axle.By means of the motor vehicle drive train 12, drive power of the first electric drive motor 14, the internal combustion engine 16, and / or the optional second electric drive motor 20 is supplied to the wheels of the motor vehicle 10. The motor vehicle 10 further comprises an energy storage device 22 for storing energy that serves to supply the first electric drive motor 14 and / or the second electric drive motor 20.

[0042] Fig. 2 shows a variant of a hybrid transmission 18 according to the invention. The hybrid transmission 18 has a first transmission input shaft 24 and a second transmission input shaft 26, which are designed to transmit drive power from the drive machines 14, 16 to the hybrid transmission 18.

[0043] The hybrid transmission 18 further includes an output shaft 28 and an intermediate shaft 30. The aforementioned transmission shafts 24, 26, 28, 30 are designed as hollow shafts. The hybrid transmission 18 also includes a countershaft 32, a first planetary gear set RS1, and a second planetary gear set RS2. A total of three spur gear pairs, designated ST1 to ST3, are arranged in the hybrid transmission 18.

[0044] The hybrid transmission has five shift elements A to E.

[0045] The first transmission input shaft 24 has a torsional vibration damper and is drivingly connected to a crankshaft 34 of the internal combustion engine 16 (not shown) via the torsional vibration damper. Furthermore, an internal combustion engine clutch K0 is arranged on the first transmission input shaft 24, which clutch is designed to decouple the hybrid transmission 18 from the internal combustion engine 16 (not shown) or to driveably connect the hybrid transmission 18 to the internal combustion engine 16 (not shown).

[0046] The first transmission input shaft 24 is drive-connected, preferably by means of a chain, to a fixed gear arranged on the intermediate shaft 30.

[0047] A sun gear of the first planetary gear set RS1 is drive-connected to the intermediate shaft 30. A planet gear carrier of the first planetary gear set RS1 is drive-connected to a sun gear of the second planetary gear set RS2. A ring gear of the first planetary gear set RS1 is drive-connected to the output shaft 28. The connection of the planet gear carrier of the first planetary gear set RS1 to the sun gear of the second planetary gear set RS2 runs radially outward around the first planetary gear set RS1.

[0048] A ring gear of the second planetary gear set RS2 is fixed, i.e., connected to a component fixed to the housing, so that the ring gear of the second planetary gear set RS2 cannot rotate. A planetary gear carrier of the second planetary gear set RS2 is drive-connected to a differential of an output 36.

[0049] A first spur gear pair ST1 has a fixed gear that is drive-connected to and arranged on the countershaft 32. Another fixed gear of the first spur gear pair ST1 is drive-connected to the output shaft 28.

[0050] In the example shown, the second spur gear pair ST2 comprises a fixed gear arranged on the countershaft 32 and a loose gear which can be drive-effectively connected to the intermediate shaft 30 by engaging the first shift element A and drive-effectively connected to the second transmission input shaft 26 by engaging the fifth shift element E.

[0051] The third spur gear pair ST3 comprises a fixed gear arranged on the second transmission input shaft 26 and meshing with an idler gear arranged on the countershaft 32. The idler gear of the third spur gear pair ST3 arranged on the countershaft 32 can be drive-connected to the countershaft 32 by engaging the fourth shift element D.

[0052] The first electric drive machine 14 is drivingly connected to the fixed gear of the third spur gear pair ST3 and consequently to the second transmission input shaft 26 by means of at least one intermediate gear not shown in detail.

[0053] By engaging the third shift element C, the second transmission input shaft 26 can be connected to the intermediate shaft 30 in a driving manner.

[0054] By engaging the second shifting element B, the intermediate shaft 30 can be drive-connected to the output shaft 28. Consequently, by engaging the second shifting element B, the first planetary gear set RS1 can be locked. It is understood that other locking variants for the first planetary gear set RS1 are also conceivable, in which two of the planetary gear set elements of the first planetary gear set RS1 are drive-connected to each other.

[0055] The shift elements A to E are preferably designed as unsynchronized shift elements, for example, claw shift elements. Furthermore, the first shift element A and the second shift element B, as well as the third shift element C and the fifth shift element E, are each combined to form a double shift element.

[0056] A particular advantage of the transmission structure of the disclosed hybrid transmission 18 is its simple technical design with only three spur gear pairs ST1 to ST3 and two planetary gear sets RS1, RS2. Furthermore, preferably only three actuators are required to control the hybrid transmission 18. The hybrid transmission 18 has a compact design, low component load, and low transmission losses. Furthermore, good gearing efficiency is achieved both in terms of the internal combustion engine and electrical transmission, as well as a good gear ratio range. Electrodynamic shifts, electromotive shifts, electrodynamic starting, and loading-into-neutral are possible. Furthermore, the arrangement of the transmission components allows the shift elements A to E to be advantageously accessed with corresponding actuators.

[0057] It is understood that the differential of the output 36 can be designed in particular as a ball differential.

[0058] Furthermore, the hybrid transmission 18 can provide an axially parallel connection of the combustion engine 16 and the first electric drive motor 14, wherein the axially parallel connection can be provided via a chain or one or more spur gears.

[0059] In the Fig. 3a to 3c are schematic representations of the switching states of the hybrid transmission 18 according to the Fig. 2 in switching matrices 38 to 42.

[0060] In Fig. 3a, a shift matrix 38 shows, in a first column, the hybrid gear stages H1 to H3, a main electric gear stage E, two electrodynamic superposition states ECVT1, ECVT2, and the charge-in-neutral state (LiN). The second to seventh columns show the shift states of the combustion engine clutch K0 and the shift elements A to E, where an "X" means that the respective shift element or the combustion engine clutch K0 is closed, i.e., connects the associated transmission components to one another in a drive-effective manner. If no entry is present, it can be assumed that the corresponding shift element or clutch is open, i.e., is not transmitting any drive power.

[0061] A first variant of the first hybrid gear stage H1.1 can be set up by engaging the combustion engine clutch K0, the first shift element A and the fifth shift element E.

[0062] A second variant of the first hybrid gear stage H1.2 can be set up by engaging the combustion engine clutch K0, the first shift element A and the fourth shift element D.

[0063] Engaging the combustion engine clutch K0, the second shift element B and the fourth shift element D sets up the second hybrid gear stage H2.

[0064] The third hybrid gear stage H3 can be established by closing the combustion engine clutch K0, the third shift element C and the fourth shift element D.

[0065] The main electric gear stage E can be set by closing the second switching element B and the third switching element C.

[0066] The first electrodynamic superposition state ECVT1 can be established by closing the combustion engine clutch K0 and the fifth switching element E.

[0067] Closing the combustion engine clutch K0 and the fourth switching element D establishes the second electrodynamic superposition state ECVT2.

[0068] A charge-in-neutral, LiN, state can be established by closing the engine clutch K0 and the third switching element C.

[0069] In Fig. 3b are arranged in a switching matrix 40 in a manner analogous to the switching matrix 38 of Fig. 3a shows the switching states for the electric gear stages E1 to E6.

[0070] To set the first electric gear stage E1, the second switching element B and the fifth switching element E must be closed.

[0071] A first variant of the second electric gear stage E2.1 can be set up by closing the third switching element C and the first switching element A.

[0072] Closing the first switching element A and the fifth switching element E establishes a second variant of the second electric gear stage E2.2.

[0073] A third variant of the second electric gear stage E2.3 can be set up by closing the third switching element C and the fifth switching element E.

[0074] The main electric gear stage E, which in this sequence would correspond to a third electric gear stage E3, can be set up, as already described above, by closing the second switching element B and the third switching element C.

[0075] Closing the third switching element C and the fourth switching element D establishes the fourth electric gear stage E4.

[0076] The fifth electric gear stage E5 can be set by closing the second switching element B and the fourth switching element D.

[0077] Closing the first switching element A and the fourth switching element D sets up the sixth electric gear stage E6.

[0078] In the Fig. 3c are analogous to the Fig. 3a and Fig. 3b shows 42 switching states for pure combustion gear stages V1, V2 in a switching matrix.

[0079] The first combustion gear stage V1 can be set by closing the combustion engine clutch K0 and the first switching element A.

[0080] Closing the combustion engine clutch K0 and the second switching element B sets up the second combustion gear stage V2.

[0081] For purely combustion engine driving, two purely combustion engine gear stages V1 and V2 are available. In addition to the closed combustion engine clutch K0 for the first combustion gear stage V1, the first shift element A must also be closed. The first combustion gear stage comprises one winding via the second spur gear pair ST2 and the first spur gear pair ST1. For the second combustion gear stage V2, the second shift element B must be closed.

[0082] When the internal combustion engine clutch K0 is open, driving is possible entirely electrically. Several electric driving gears E1 to E6 are available for this purpose. The main electric driving gear, or the main electric gear stage E, is formed by closing the third shift element C and the second shift element B. From this shift state, the internal combustion engine 16 can be started directly in the second hybrid gear stage H2.

[0083] If the fifth shifting element E is closed, an EDA state occurs at the first planetary gear set RS1. The internal combustion engine 16 is connected to the sun gear of the first planetary gear set RS1, with the first electric drive motor 14 supporting the torque of the internal combustion engine 16 on the ring gear of the first planetary gear set RS1. The planet gear carrier of the first planetary gear set RS1 is drive-effectively connected to the output 36 via a second planetary gear set RS2. This enables EDA forward starting. From this EDA mode, the internal combustion engine 16 can be shifted into the first variant of the first hybrid gear stage H1.1 by closing the first shifting element A, preferably during synchronous operation, in addition to the already closed internal combustion engine clutch K0 and the fifth shifting element E.

[0084] After starting via the second electrodynamic superposition state ECVT2, in which the combustion engine clutch K0 and the fourth shift element D are closed, it is possible to shift directly into the second variant of the first hybrid gear stage H1.2 by closing the first shift element A, preferably during synchronous operation, in addition to the already closed combustion engine clutch K0 and the closed fourth shift element D.

[0085] A powershift from the first variant of the first hybrid gear stage H1.1 to the second variant of the first hybrid gear stage H1.2 and finally to the second hybrid gear stage H2 can, for example, occur as follows. The first shifting element A and the fifth shifting element E are closed. The fifth shifting element E is opened, so that the first pure combustion gear stage V1 is engaged. In synchronous operation, the fourth shifting element D is closed, so that the shift is made to the second variant of the first hybrid gear stage H1.2. The first shifting element A is then opened to enter the second electrodynamic superposition state ECVT2. Here, the combustion engine speed is reduced until the intermediate shaft 30 and the output shaft 28 are running synchronously. In synchronous operation, the second shifting element B is closed and the first planetary gear set RS1 is locked. The second hybrid gear stage H2 is then engaged.

[0086] If only the internal combustion engine clutch K0 and the third switching element C are closed, the first electric drive motor 14 can be connected to the internal combustion engine 16 independently of the output 36. The first electric drive motor 14 and the internal combustion engine 16 then rotate at a fixed speed ratio to one another. This allows, on the one hand, a start of the internal combustion engine 16 with the first electric drive motor 14, and, on the other hand, the first electric drive motor 14 can be operated by the internal combustion engine 16 as a generator and charge the electrical energy storage device 22 or supply electrical consumers. A consumer can also be a second electric drive motor 20, as shown, for example, in Fig. 1, which drives the motor vehicle 10 on another vehicle axle. Such drive technologies are therefore referred to as electric rear axles.

[0087] All pure combustion gear stages V1, V2 can be switched in series via the charge-in-neutral state.

[0088] A transition from the charge-in-neutral LiN state to the first variant of the first hybrid gear stage H1.1 is possible if the third switching element C is first opened and, after synchronization, the fifth switching element E is closed. Synchronization of the first switching element A is generated via the first electrodynamic superposition state ECVT1, which is then closed.

[0089] Is, as for example in Fig. If, as shown in Figure 1, an electric rear axle is present, an all-wheel drive system can be created using this combination. For example, a DHT transmission, i.e., a Dedicated Hybrid Transmission, with the internal combustion engine 16 and the first electric drive motor 14, can be designed as a pure front-wheel drive, with additional rear-axle drive being provided by the separate second electric drive motor 20. The electrodynamic superposition states ECVT1, ECVT2 are power-split driving ranges for the internal combustion engine 16, in which battery-neutral operation is also possible.

[0090] This allows, for example, traction support to be provided by the second electric drive motor 20. The second electric drive motor 20 can support the traction at the rear axle when shifts are necessary in the hybrid transmission 18, during which the output 36 of the hybrid transmission 18 becomes load-free. An example of such a transition is when the vehicle is first driven purely electrically with the first electric drive motor 14 and / or the second electric drive motor 20 and then the combustion engine 16 is to be started in neutral using the first electric drive motor 14.

[0091] In Fig. 4 shows a further variant of a hybrid transmission 18 according to the invention. In contrast to the Fig. In the embodiment shown in Figure 2, the third spur gear pair ST3 comprises two fixed gears. Furthermore, the fixed gear of the second spur gear pair ST2 arranged on the countershaft 32 and the fixed gear of the first spur gear pair ST1 arranged on the countershaft 32 are drivingly connected to one another by a hollow shaft 44 arranged on the countershaft 32. The hollow shaft 44 can be drivingly connected to the countershaft 32 by engaging the fourth shift element D.

[0092] In Fig. 5 shows a further variant of a hybrid transmission 18 according to the invention. In contrast to the Fig. 4, the hybrid transmission 18 comprises the Fig.5 does not have a second planetary gear set RS2. Furthermore, a hollow output shaft 46 is arranged on the countershaft 32. A planetary gear carrier of the first planetary gear set RS1 is drive-connected to the hollow output shaft 46 by means of a fourth spur gear pair ST4. Furthermore, a differential of the output 36 is drive-connected to the hollow output shaft 46 by means of a fifth spur gear pair ST5.

[0093] This eliminates the need for a planetary gear set, allowing an output ratio to be achieved using the fourth spur gear pair ST4 and the fifth spur gear pair ST5. Furthermore, this allows the axial length of the hybrid transmission 18 to be reduced.

[0094] Not shown in the figures, an alternative connection of the first planetary gear set RS1 is also conceivable. In the alternative connection, the connections to the sun gear and ring gear are swapped. The output 36 remains connected to the planet gear carrier of the first planetary gear set RS1. The combustion engine 16 is connected to the ring gear of the first planetary gear set RS1 via the intermediate shaft 30, and the first electric drive motor 14 is connected to the sun gear of the first planetary gear set RS1 via spur gear stages and / or shifting elements. This allows a smaller first electric drive motor 14 to be used, since a lower support torque needs to be applied by the first electric drive motor 14 during electrodynamic starting and electrodynamic shifting.In particular, during electrodynamic starting, the first electric drive machine 14 can be operated as a generator for a longer period, since the generator operation is left later as the driving speed increases.

[0095] Furthermore, the separating clutch K0 can be designed as a positive-locking or friction-locking shifting element. It is understood that a further electric machine, in particular in the form of a high-voltage starter generator, can be arranged on the first transmission input shaft 24. The high-voltage starter generator can preferably be drivingly connected to the first transmission input shaft 24 via a gear chain.

[0096] The invention has been comprehensively described and explained with reference to the drawings and the description. The description and explanation are to be understood as exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other embodiments or variations will become apparent to those skilled in the art upon use of the present invention and upon careful analysis of the drawings, the disclosure, and the following claims.

[0097] In the patent claims, the words "comprising" and "having" do not exclude the presence of further elements or steps. The undefined article "a" or "an" does not exclude the presence of a plurality. A single element or a single unit can perform the functions of several of the units recited in the patent claims. The mere mention of some measures in several different dependent patent claims should not be understood to mean that a combination of these measures cannot also be used advantageously. Reference symbols in the patent claims are not to be understood as limiting. A method for operating a motor vehicle drivetrain 12 can, for example, be implemented in the form of a computer program that is executed on a control unit for the motor vehicle drivetrain 12.A computer program may be stored / distributed on a non-volatile storage medium, such as optical storage or a solid-state drive (SSD). A computer program may be distributed together with hardware and / or as part of hardware, such as via the Internet or via wired or wireless communication systems. Reference symbol 10 motor vehicle 12 Automotive powertrain 14 first electric drive machine 16 Combustion engine 18 hybrid transmissions 20 second electric drive motor 22 energy storage 24 first transmission input shaft 26 second transmission input shaft 28 Output shaft 30 Intermediate shaft 32 Countershaft 34 Crankshaft 36 downforce 38 Switch matrix 40 switching matrix 42 Switch matrix 44 Hollow shaft 46 Output hollow shaft AE switching elements K0 internal combustion engine clutch RS1 first planetary gear set RS2 second planetary gear set ST1-ST5 spur gear pairs

Claims

[1] Hybrid transmission (18) for a motor vehicle drive train (12) of a motor vehicle (10), comprising: a first transmission input shaft (24) for operatively connecting the hybrid transmission (18) to an internal combustion engine (16) of the motor vehicle; a second transmission input shaft (26) for operatively connecting the hybrid transmission (18) to a first electric drive motor (14) of the motor vehicle (10); an intermediate shaft (30) which is drivingly connected to the first transmission input shaft (24); an output shaft (28); a first planetary gear set (RS1) for operatively connecting the hybrid transmission (18) with an output (36) which is connected to the intermediate shaft (30) and the output shaft (28); a countershaft (32); spur gear pairs (ST1, ST2, ST3, ST4, ST5) arranged in several gear set levels; and several gearshift devices with shift elements (A, B, C, D, E) for engaging gear steps, wherein a gear of a first spur gear pair (ST1) and a gear of a second spur gear pair (ST2) are drivingly connected to one another; the intermediate shaft (30) is drivingly connected to a sun gear or a ring gear of the first planetary gear set (RS1); a differential of the output (36) comprises a differential shaft which is designed as a solid shaft and is surrounded at least in sections by the intermediate shaft (30), the second transmission input shaft (26) and the output shaft (28); and an axial length of the differential shaft is greater than an axial length of the output shaft (28) and the differential shaft completely penetrates the output shaft (28). [2] Hybrid transmission (18) according to the preceding claim, wherein the hybrid transmission (18) comprises a second planetary gear set (RS2) which is drivingly connected to the first planetary gear set (RS1) and a differential of the output (36). [3] Hybrid transmission (18) according to claim 2, wherein a ring gear is fixed in the second planetary gear set (RS2), a planetary gear carrier is connected to the differential of the output (36) and a sun gear is drivingly connected to a planetary gear carrier of the first planetary gear set (RS1). [4] Hybrid transmission (18) according to claim 1, wherein an output hollow shaft (46) is arranged on the countershaft (32); a planetary gear carrier of the first planetary gear set (RS1) is drivingly connected to the output hollow shaft (46) by means of a fourth spur gear pair (ST4); and a differential of the output (36) is drivingly connected to the output hollow shaft (46) by means of a fifth spur gear pair (ST5). [5] Hybrid transmission (18) according to claim 1, wherein the first spur gear pair (ST1) and the second spur gear pair (ST2) are connected to one another by means of a hollow shaft (44) and are arranged on the countershaft (32). [6] Hybrid transmission (18) according to one of the preceding claims, wherein a planetary gear carrier of the first planetary gear set (RS1) is drivingly connected to the output (36); the sun gear of the first planetary gear set (RS1) is drivingly connected to the intermediate shaft (30) and the ring gear of the first planetary gear set (RS1) is drivingly connected to the output shaft (28); or the ring gear of the first planetary gear set (RS1) is drivingly connected to the intermediate shaft (30) and the sun gear of the first planetary gear set (RS1) is drivingly connected to the output shaft (28). [7] Hybrid transmission (18) according to one of the preceding claims, wherein the second transmission input shaft (26), the intermediate shaft (30) and the output shaft (28) are arranged coaxially to one another; the first transmission input shaft (24), the second transmission input shaft (26), the intermediate shaft (30) and the output shaft (28) are designed as hollow shafts; and the second transmission input shaft (26) and the intermediate shaft (30) surround the output shaft (28) at least in sections. [8] Hybrid transmission (18) according to one of the preceding claims, wherein the first transmission input shaft (24) comprises an internal combustion engine clutch (K0) for releasably drivingly connecting the first transmission input shaft (24) to the internal combustion engine (16). [9] Hybrid transmission (18) according to one of the preceding claims, wherein a first shifting element (A) is designed to drive-effectively connect the intermediate shaft (30) to the output shaft (28) by means of the second spur gear pair (ST2) and the first spur gear pair (ST1); a second shifting element (B) is designed to block the first planetary gear set (RS1); a third shift element (C) is designed to drive-effectively connect the second transmission input shaft (26) to the intermediate shaft (30); a fourth switching element (D) is designed to drive-effectively connect the first electric drive machine (14) to the output shaft (28) by means of the third spur gear pair (ST3) and the first spur gear pair (ST1); and / or a fifth switching element (E) is designed to drive-effectively connect the first electric drive machine (14) to the output shaft (28) by means of the second spur gear pair (ST2) and the first spur gear pair (ST1). [10] Hybrid transmission (18) according to one of the preceding claims, wherein the switching elements (A, B, C, D, E) are designed as positive-locking switching elements; and / or at least two of the switching elements (A, B, C, D, E) are designed as double switching elements and can be actuated by a double-acting actuator. [11] Motor vehicle drive train (12) for a motor vehicle (10), comprising: a hybrid transmission (18) according to one of the preceding claims; an internal combustion engine (16) connectable to the first transmission input shaft (24); and a first electric drive motor (14) which is drivingly connected to the second transmission input shaft (26). [12] Motor vehicle drive train (12) according to claim 11, wherein the motor vehicle drive train (12) comprises a further electric machine which is drivingly connected to the first transmission input shaft (24) and the first electric drive machine (14) can be controlled as a starter generator for starting the internal combustion engine (16); and / or can be controlled as a charging generator for charging an energy storage device (22). [13] Method for operating a motor vehicle drive train (12) according to claim 11 or 12. [14] Motor vehicle (10) with: a motor vehicle drive train (12) according to claim 11 or 12; and an energy storage device (22) for storing energy to supply the first electric drive machine (14) and / or the second electric drive machine (20).

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